Electronic candle having tilt sensor and blow sensors

ABSTRACT

An electronic candle includes a housing, an LED light source, a battery, and one or more sensors to detect a blow of air or a tilt of the electronic candle. The electronic candle further includes a microprocessor that is coupled to the LED light source, to the blow sensor and to the tilt sensor. The microprocessor is programmed to control illumination produced by the LED light source, to receive signals indicative of the detection of a blow, and to detect a tilt of the electronic candle.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a continuation of U.S. patent applicationSer. No. 14/672,819, filed Mar. 30, 2015, which is a continuation ofU.S. patent application Ser. No. 13/908,571 filed Jun. 3, 2013, which isa continuation of U.S. patent application Ser. No. 13/526,067 filed Jun.18, 2012, now U.S. Pat. No. 8,454,190, which is a continuation of U.S.patent. Ser. No. 12/237,337, filed Nov. 18, 2008, now U.S. Pat. No.8,210,708, each of which is hereby incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION

I. Field of the Invention

This invention relates generally to electronic candles used to simulateactual wax candles, and more particularly to a system for recharging alarge plurality of such candles.

II. Discussion of the Prior Art

There are artificial candles on the market presently that replicate thelook of a burning wax candle, but which incorporate a yellow LED and asuitable electronic controller for imparting a flickering illuminationof the LED to simulate the glow of a burning wax candle. However, forthe most part, those candles embody a rechargeable battery and a circuitthat had to be plugged into a DC current source to effect recharging ofthe candle, one at a time.

Many restaurants often include a so-called votive candle on each tablein the restaurant to add to the ambience of the place. A votive candleis generally 2.0 inches in height by 1.5 inches in diameter and iscontained in a suitable holder, such as a glass cup. If one wished tosubstitute an electronic artificial candle for the real thing, a waywould have to be devised to simultaneously recharge a large plurality ofsuch artificial candles so that when fully charged, they may bedistributed throughout the restaurant and turned on upon arrival of apatron at a given table.

The prior art, as represented by U.S. Pat. No. 6,819,080 to Barbeau etal, teaches a stand-alone recharging platter capable of charging a setnumber of artificial candles. Such stand-alone platters have a powercord for supply an electrical charge. If a restaurant needs to chargemore candles than the platter is adapted to handle, the restaurant mustplug multiple platters into multiple wall sockets.

Another concern on the part of a restaurant owner is the potential lossof such a candle through theft. The artificial candles, being bothattractive and of more than negligible cost, loss through theft can be aproblem.

A need therefore exists for a decorative artificial candle design thatcan be used in a restaurant environment as a table decoration and thatis adapted to be recharged simultaneously with many other identicalcandles in unison rather than individually.

A need further exists for an artificial candle design that incorporatesfeatures that discourage theft.

A further need is an artificial candle that is more realistic in itsoperation than existing prior art artificial electronic candlescurrently available. Specifically, a need exists for an artificialcandle that more accurately simulates a real wax candle in that it canbe extinguished by a puff of air blown at it at close range.

SUMMARY OF THE INVENTION

The present invention provides a charging stand or tray that can beconcatenated with a plurality of identical trays where each tray iscapable of supporting a plurality of individual artificial electroniccandles as they are simultaneously having their internal batteriesrecharged. Each of the individual candles may incorporate a positionsensitive module capable of detecting whether a candle is otherwise thanin an upright position and to provide an audible signal unless thecandle is returned to its upright position within a prescribed timeinterval.

In accordance with a further feature of the invention, a suitabletransducer can be incorporated into the individual candles where thetransducer is capable of detecting pressure and temperature changesoccasioned by a person blowing his/her breath onto the candle andcausing the LED light source used to simulate the flame to beextinguished.

DESCRIPTION OF THE DRAWINGS

The foregoing features, objects and advantages of the invention willbecome apparent to those skilled in the art from the following detaileddescription of a preferred embodiment especially when considered inconjunction with the accompanying drawings in which like numerals in theseveral views refer to corresponding parts:

FIG. 1A is a pictorial view showing four charging trays joined togetherand populated with a plurality of artificial candles;

FIG. 1B is an enlarged view of four charging trays connected togetherand showing the plug and socket detail;

FIG. 2 is a side elevation view of the artificial candle with thedecorative outer shroud removed;

FIG. 3 is a cross-sectional view taken through the artificial candleincorporating an anti-theft feature;

FIG. 4 is a view of a charging tray populated with artificial candlesand cross-sectioned to show the engagement between a transformer primarywinding forming part of the charging tray and a secondary windingdisposed in the artificial candle;

FIG. 5 is an electrical schematic diagram of the artificial candleincorporating the anti-theft feature;

FIG. 6 is a schematic electrical diagram of the artificial candleincorporating the blow-out feature; and

FIG. 7 is an electrical schematic diagram of an inner connected pair ofcharging trays and a current limiter circuit used therewith.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1A, there is shown a plurality of electricallyand mechanically interconnected artificial candle charging trays 2, 4,6, 8 that are populated with a plurality of battery-operated artificialcandles 10. Without limitation, each charging tray may hold up to adozen artificial candles in which a rechargeable DC battery is connectedthrough a semiconductor switch to a yellow LED and where the switch is,in tum, controlled by a programmed microprocessor chip such that the LEDmay be made to flicker much like the light given off by a real waxcandle. Just how this is achieved will be explained in greater detailherein below.

With continued reference to FIG. 1A, power for the charging tray isderived from a conventional AC/DC adapter that when plugged into a wallsocket at 110 volts produces a 12 volt DC output. Connected in the cableleading from the adapter 12 to the first recharging tray 2 is a currentlimiter circuit 14.

FIG. 1B illustrates the manner in which plural trays, 2, 4, 6 and 8, canbe concatenated so that each is supplied with power from the AC to DCadapter, via the current limiter circuit 14. The DC input from thecurrent limiter 14 enters through a plug 15 that projects laterally froma side edge 17 of the tray 2. Formed inwardly in the opposed sidesurface 19 of the tray 2 is a female socket dimensioned to accommodatethe insertion of a male plug 21 that projects from the side surface ofan identical tray 4. Likewise, tray 6 has a plug 23 mating with a socketin the side surface of the tray 4, etc. Contained within the hollowinterior of the trays 2, 4, 6 and 8 are printed circuit boards andwiring that operatively connect the contacts of the plug 15 tocorresponding terminals in the socket into which the plug 21 of the tray4 is inserted. The manner of inner connection is shown in the electricalschematic diagram of FIG. 7.

Referring next to FIGS. 2 and 3, each of the battery operated artificialcandles comprises a yellow LED 16 that simulates the candle flame. It issurrounded by a translucent bulb 18 (FIG. 3) having the tapered shape ofa flame and used to defuse the light emanating there through. The LED 16projects out through an aperture in the top surface 20 of the moldedplastic candle housing 22 or shroud, which is generally a hollowright-circular cylinder that contains the electronic circuitry forpowering the LED 16.

With continued reference to FIGS. 2 and 3, a rechargeable battery 24 ispositioned directly below a socket 26 for the LED 16 and adjacent theunderside of a printed circuit board assembly 28 on which much of thecircuitry of FIG. 7 is disposed. A pushbutton “on/off’ switch 30 isdisposed within the housing 22 and is accessible through an apertureformed in the base 32 of the candle. The base also includes a bore 34and surrounding the bore 34 is an electrical coil 36 or windings which,as will be further explained, acts as the secondary winding of atransformer whose primary winding is disposed about a ferrite core in ahollow post on the charging tray that is adapted to fit within the bore34 of the artificial candle. The arrangement is more clearly shown inthe cross-sectioned view of FIG. 4.

As shown in FIG. 4, the recharging trays for the artificial candlesinclude a hollow, box-like base 38 formed of injection molded plastic.Disposed within the interior of the base 38 is a printed circuit board40 that contains the circuitry of one of the two recharging traysillustrated in the electrical schematic diagram of FIG. 7.

Formed into the top surface of the base 38 is a plurality of indentedcircular sockets dimensioned to receive a bottom portion of anartificial candle in each. Centrally located in each of the sockets andprojecting vertically from the center thereof are cylindrical posts 42.Contained within each such post is a magnetic core 43 encircled by coilwindings, as at 44, and which form the primary winding of a transformerthat is inductively coupled to the coil 36 that surround the bore 34 inthe candle when the candles are resident in the sockets of the base 38.

Referring back to FIG. 2, also contained within the cylindrical housing22 of the artificial candle is a motion sensor 46. The motion sensor 46includes three small tubes 48, 50 and 52 that contain a conductive ballin the lumens thereof, the balls being free to move between electricalcontacts disposed at opposed ends of each of the tubes. Thus, forexample, when the artificial candle is resting on a flat horizontalsurface, the conductive balls will be at the lower end of each of thetubes 48, 50 and 52, but when the candle is tipped from its uprightposition, gravity will cause the conductive balls to shift in positionto close a different set of contacts, thus indicating that the candle isno longer upright.

Also visible in FIG. 2 is a battery-operated buzzer 54 which will bemade to sound whenever the artificial candle is not in its uprightposition for a predetermined length of time. Thus, for example, should arestaurant patron attempt to make off with a candle by placing it in apocket or purse, the device will give off an audible sound to alertrestaurant personnel that a candle is being taken.

FIG. 5 is an electrical schematic diagram of the circuitry containedwithin the housing 22 of the artificial candle incorporating theanti-theft feature. The transformer T has a center tapped winding wherethe center tap is connected by conductors 100 and 102 to circuit ground.The opposed outer ends of the secondary winding are connected throughrectifier diodes D201 and D202 to a junction point VCC. A smoothingcapacitor C201 is connected between that junction and the center tapterminal of the transformer winding, T.

Connected between the junction VCC and ground is a series combination ofan NPN transistor Q4 and a resistor R14. Connected between the baseelectrode of Q4 and ground is a reference Zenar diode ZD1 and connectedbetween the junction VCC and the base electrode of Q4 is a resistor R1.

A PNP transistor Q1 has its emitter electrode coupled to the junctionVCC by a current limiting resistor R2 and the collector electrode of Q1is connected through a diode D1 to a junction point VDD. The baseelectrode of Q1 is connected to ground through a series combination of aresistor R4 and the emitter to collector path of a PNP transistor Q2.More particularly, the emitter electrode of Q2 is connected directly toground while its collector electrode connects to the base electrode ofQ1 via the resistor R4.

A pair of diodes D4 and D5 are connected in series between the junctionVCC and the base electrode of transistor Q1 the purpose of which is toapply an appropriate bias for transistor Q1.

Control over the mode of operation of the candle is dictated by aprogrammed microprocessor U1 which preferably comprises a Type FS260, an8-bit microprocessor. A push-button off/on switch for the artificialcandle, S1, is connected between ground and input pin B1 of themicroprocessor and a capacitor C6 is connected directly in parallel withthe switch SL Connected between input terminals BO and B2 are positionedsensing switches S301 and S302 and S303. These are the same devices asreferred to by reference numerals 48, 50 and 52 in the drawing of FIG.2. A debounce capacitor C5 is connected in parallel with these threeposition sensitive switches.

An NPN transistor Q5 has its emitter electrode tied to ground and itscollector electrode connected to the input terminal B3 of themicroprocessor U1. The base electrode of Q5 is connected through abiasing resistor R3 to the junction point between the emitter electrodeof Q4 and the resistor R14. That junction is also connected by means ofa conductor 103, a diode D2, and a resistor R17 to output terminal A3 ofthe microprocessor U1. The common junction between the diode D2 and theresistor R17 is coupled by a resistor R15 to the reset terminal RETB ofthe microprocessor and by a conductor 104 to the VDD terminal of themicroprocessor U1.

A first LED, preferably green in color, has its anode electrode tied tothe conductor 104 and its cathode electrode connected, via a resistorR7, to the output terminal B4 of the microprocessor. Likewise, a secondLED, preferably red in color, has its anode electrode connected to theconductor 104 and its cathode electrode connected by a resistor R6 tooutput terminal B5 of the microprocessor.

The output terminal B6 of the microprocessor is connected through aseries resistor R11 to the base electrode of a PNP transistor Q6 whoseemitter electrode connects to the positive terminal of a rechargeablebattery BT1 and whose negative electrode is connected to ground. Therechargeable battery, for example, may be a 3.6 volt 330 ma lithiumbattery, but limitation to that type of rechargeable cell is not to beinferred.

The collector electrode of a transistor Q6 connects to ground through aresistor R12 and a yellow LED, labeled LED 1, which is the flame LED 16in FIGS. 2 and 3 of the drawings. The positive battery terminal BT+ isalso connected through a diode D3 to the VDD terminal of themicroprocessor thereby supplying its operating voltage. The cathode ofthe diode D3 connects to conductor 104 and a capacitor C3 connectsbetween that conductor and ground. A resistor R16 couples the VDDterminal of the microprocessor to its OSC1 terminal.

With continued reference to FIG. 5, the anode electrode of the diode D3connects through a series resistor R9 and a capacitor C7 to ground.Connected directly in parallel with the capacitor C7 is a furtherresistor R10. The common terminal between the resistor C7, the resistorR9 and the resistor R10 is tied to the input terminal A1 of themicroprocessor.

Programmable shunt regulator U2 is connected between the microprocessorinput terminal A4 and ground and its reference electrode is connected bymeans of a capacitor C4 to ground. The reference electrode is alsodirectly connected to the device's cathode.

Completing the circuit of FIG. 5 is an audible signaling device orbuzzer B1 having a first terminal thereof connected to the VDD terminal,i.e., the battery's positive terminal and the second terminal of thebuzzer B1 connects through an NPN transistor switch Q3 to ground. Thebase electrode of Q3 has a resistor R8 connecting it to the terminal A5of the microprocessor U1.

In operation, and assuming that the battery potential BT+ is below acertain potential and it is appropriately mounted on the charging traywith the post 42 located in the bore 34, transistor Q1 will be forwardbiased and a DC current resulting from rectification of the inducedvoltage across the secondary winding of the transformer T becomesavailable to charge the battery. When the battery becomes charged to thepoint where its voltage BT+ is at a predetermined value, themicroprocessor is programmed to output a signal on its terminal A2 toreverse bias the transistor Q2 which has the effect of shutting off thecharging current flow through the transistor Q1 to the battery.

With the battery fully charged and assuming the candles have beenremoved from the tray, depression on the on/off switch S1 inputs aground signal to terminal B1 of U2 which has the effect of driving thetransistor Q6 into conduction, whereby current flows to the candle lampLED1 causing it to glow. The candle flame LED1 is made to flicker by themicroprocessor suitably varying the on/off state of the transistor Q6.However, if the on/off switch S1 is depressed a second time, themicroprocessor is programmed to cause a steady current to flow throughtransistor Q6, such that LED1 no longer flickers. A third depression ofthe on/off switch is effective to turn off the candle.

Assuming that the battery is fully charged, the candle has been removedfrom the base 38 and that the on/off switch has been depressed eitheronce or twice in succession and then the candle set down on a flat,horizontal surface, such as on a patron's table, the LED1 will continueto glow. However, if the patron should now pick up the candle from thetable and, in doing so, tip it so that its top surface 20 isnon-horizontal, one or more of the position sensitive switches S301,S302 and S303 will reverse state and input a signal betweenmicroprocessor terminals B0 and B2. Upon detection of this condition fora programmed period, say 5 seconds, the microprocessor will issue asignal on output terminal A5 to turn on the transistor Q3 and complete acircuit from the battery through the buzzer to ground causing the buzzerto emit an audible signal that can attract attention of a restaurantemployee. Turning on the buzzer B1 also results in the LED2 flashing onand off at one second intervals which is a further attention getter.This state will continue until the candle is returned to the chargingtray that is located to be accessible only to restaurant employees.

Turning next to FIG. 6, it is substantially identical in itsconstruction to that of FIG. 5 except that the buzzer and positionsensitive switches S301, S302 and S303 are eliminated and replaced withcircuitry that adds further realism to the artificial candle.Specifically, if the flame LED is glowing in either its blink mode orits steady mode and a patron blows air at the flame, the flame will beextinguished.

As seen in FIG. 6, connected between the microprocessor input terminalsB0 and B2 is the circuitry shown enclosed by the broken line box 105. Itincludes a PVDF pyro/piezo film transducer CY1 that possesses theproperty of being able to convert a temperature change and pressure waveinto an electrical signal proportional to the amount of change. Thissignal is amplified by a two-stage amplifier including the transistorsQ3 and Q7 and the microprocessor is programmed so that upon receipt ofthe “blow” signal from the transducer CY1, the transistor Q6 is turnedoff, thereby extinguishing LED1.

FIG. 7 is an electrical schematic diagram of the circuitry used tosimultaneously recharge the batteries of a plurality of artificialcandles heretofore described. The 110 volt AC to 12 volt DC adapter 12provides its output to the current Imitator circuit 14 contained withinthe broken line box 110. The current Imitator circuit functions to limitthe current draw by the attached charging trays to a maximum of 3.2amperes and thereby preventing overloading of the adapter 12. Should thecurrent draw by the connected recharging trays reach the limit of 3.2amperes, the current Imitator automatically cuts off the power beingdelivered to the recharging trays. The current imitator circuit includesa Type TL431 shunt regulator 112 whose cathode and reference electrodeare connected through a jumper selectable voltage divider to thenon-inverting input of an LM393 operational amplifier 114 and whoseoutput connects to a Type IRFL024N power MOSFET operatively connectedbetween a wire in the cable that is adapted to plug into the chargingtray and ground. The inverting input of the op amp 114 connects througha manually operated reset switch 118 to ground.

The cathode electrode of the shunt regulator 112 is also coupled througha resistor 120 to the non-inverting input of an operational amplifier122. The resistor 120 along with a further resistor 123 constitutes avoltage divider. The cathode electrode of the shunt regulator 112 alsoconnects through a parallel RC circuit 124 to the inverting input of theop amp 122. The op amp 122 has its output electrode connected through adiode 126 to the inverting input of the op amp 114 and through aresistor 128 to the gate electrode of the power MOSFET 116.

Those skilled in the art will appreciate that the shunt regulator 112functions much like a Zenar diode to provide a predetermined referencefor the op amps 114 and 122 and that when the current being drawn fromthe AC/DC adapter 12 approaches 3.2 ampere, the power MOSFET 116 isdriven into conduction effectively disconnecting the AC/DC adaptersource from its load.

The recharging tray circuits are shown enclosed by broken line boxes 130and 133. While only two such recharging tray circuits are shown in FIG.7, it is to be appreciated that additional trays may be concatenated byoperatively joining them to the two conductor cable 132, via plugs as at134 and 136, that are adapted to mate with sockets or jacks 138 and 140,respectively, in the manner explained with reference to FIG. 1B. In thatthe two illustrated recharging trays are identical, it will only benecessary to explain the constructional features of one of them and, inthis regard, attention will be given to the circuitry shown enclosed bythe broken line box 130.

With the plug 134 mated with the jack 138, a current path is establishedto a conductor 142 that connects to the center tap terminals of theprimary windings of transformers T1 through T12. It will be recalledthat the cores of the transformers T1-T12 are individually disposedwithin hollow posts projecting upward from the center of the pockets onthe charging tray. The “ON” state of the charging tray is indicated bymeans of a pair of LEDs 144 connected between conductor 142 and ground.

The two outer terminals of the center tapped windings of transformers T1through T12 are connected through, for example, MOSFET switches 146,147, 148, and 149, and the ON/OFF state of these switches is controlledby one of the pulse width modulator chips 150 and 152. Withoutlimitation, they may each comprise a Type SG3525A integrated circuitdevice available from ST Microelectronics or an ESM6820A dual N-Channelenhancement mode FET. Such circuits are frequently used in the design ofvarious types of switching power supplies. Thus, the duty cycle of thepulsitile current made to flow through the transformer windings of T1through T12 can be controlled. To protect the MOSFET switches 146-149from exposure to peak voltages generated by the coils of the transformerwindings, a diode 153 and a parallel RC circuit 155, 157 is connectedbetween the outer ends of the coils and their center tap.

The switching rate of the MOSFET switches 146-149 is controlled by theselection of the RC time constant of the circuit connected to the “R”and “C” input terminals of the integrated pulse width modulator chips150 and 152. The RC timing circuit for the pulse width modulator chip150 is identified by numeral 154 in FIG. 7.

When the artificial candles are placed on the recharging tray in themanner shown in FIG. 4, the winding contained within the candle housingis exposed to the magnetic flux generated by the transformer coils ofT1-T12 and converted by the rectifiers D201 and D202 to a DC current forrecharging the candles' batteries 24.

The microprocessor chip U1 contained within the candle causes thebattery to be charged with only 30% of the maximum set current for aperiod of 20 minutes. Following that, the batteries in the candles willbe charged at 100% of the set current until such time that it isdetected that the battery voltage has reached 4.2 volts, indicating afully charged condition. At this time, the glowing red LED (LED 2) willswitch off and the green LED (LED 3) is illuminated to indicate a fullycharged condition of the candle battery. As already mentioned, themicroprocessor U1 in the candle receives a signal when the battery hasbecome fully charged up to 4.3 volts and will cause the transistor Q1 tobecome non-conductive, thereby cutting off the charging current.

This invention has been described herein in considerable detail in orderto comply with the patent statutes and to provide those skilled in theart with the information needed to apply the novel principles and toconstruct and use such specialized components as are required. However,it is to be understood that the invention can be carried out byspecifically different equipment and devices, and that variousmodifications, both as to the equipment and operating procedures, can beaccomplished without departing from the scope of the invention itself.

What is claimed is:
 1. An electronic candle, comprising: a housing; an LED light source positioned at least partially within the housing; a battery for energizing the LED light source; a microprocessor coupled to the LED light source and programmed to control illumination produced by the LED light source; a sensor positioned inside the housing to detect a blow of air directed at the electronic candle, the sensor coupled to the microprocessor and including a two-stage electronic circuit that includes one or more transistors and one or more resistors configured to generate a signal in response to detection of the blow and to provide the signal to the microprocessor; and an additional sensor coupled to the microprocessor and configured to detect a tilt of the electronic candle.
 2. The electronic candle of claim 1, wherein the sensor includes a pyroelectric or a piezoelectric transducer coupled to the two-stage electronic circuit.
 3. The electronic candle of claim 1, wherein the sensor is capable of converting one or both of a temperature change or a pressure wave into an electrical signal.
 4. The electronic candle of claim 1, wherein the microprocessor is programmed to cause the LED light source to produce illumination in a blinking pattern or a steady pattern.
 5. The electronic candle of claim 1, wherein the microprocessor is programmed to turn off the LED light source upon detection of the signal indicative of the blow.
 6. The electronic candle of claim 1, wherein the microprocessor is programmed to vary an electrical signal provided to the LED light source to cause flickering of the LED light source.
 7. The electronic candle of claim 1, wherein the LED light source is coupled to the microprocessor through a semiconductor switch, and the microprocessor is configured to extinguish the LED light source upon detection of the signal indicative of the blow by turning off the semiconductor switch.
 8. The electronic candle of claim 1, further comprising an translucent flame-shaped component projecting outward from the top portion of the housing that is configured to diffuse light that emanates therethrough.
 9. The electronic candle of claim 1, further comprising an additional LED light source, wherein the microprocessor is programmed to cause the additional LED light source to blink upon detection of a signal from the additional sensor indicative of the tilt of the electronic candle.
 10. The electronic candle of claim 1, wherein the additional sensor is a motion sensor.
 11. The electronic candle of claim 1, wherein the battery is a lithium ion battery.
 12. The electronic candle of claim 1, further comprising a base that includes a bore, wherein the bore is adapted to mate with a post of a charging device.
 13. The electronic candle of claim 1, wherein the housing is cylindrical in shape.
 14. The electronic candle of claim 1, wherein the battery is a rechargeable battery and the electronic candle further includes an electric coil that is electrically coupled to the rechargeable battery and is configured to supply charge to the rechargeable battery.
 15. The electronic candle of claim 14, wherein the electric coil is configured to supply the charge to the rechargeable battery due to induction coupling with a magnetic element of a charging base.
 16. The electronic candle of claim 1, further including a switch positioned at a bottom section of the electronic candle, the switch configured to (a) turn the electronic candle on or off, or (b) to select a particular mode of operation of the electronic candle.
 17. The electronic candle of claim 16, wherein the particular mode is one of a blinking mode or a steady illumination mode.
 18. The electronic candle of claim 1, wherein the microprocessor is programmed to activate a buzzer upon detection of a signal from the additional sensor indicative of the tilt of the electronic candle.
 19. The electronic candle of claim 18, wherein the microprocessor is programmed to activate the buzzer upon detection of the signal indicative of the tilt of the electronic candle for a predetermined period of time. 